奥巴马宣布就中国对美国生产的汽车征收关税一事向世贸组织提出了申诉

U.S. President Barack Obama says his government will fight to hold China accountable for practices harming American automakers.

Speaking at a campaign stop near  Toledo, Ohio Thursday, Mr. Obama said Americans need a "fair playing field." He announced a new complaint with the World Trade Organization on more than $3 billion in allegedly unfair Chinese duties on American-made cars.

Toledo is home to a big auto plant complex. Mr. Obama told the crowd that six previous WTO challenges to China have been successful.

Mr. Obama is spending Thursday and Friday in Ohio and Pennsylvania, two crucial states in the November general election.

He carried both in the 2008 election, and recent opinion polls show him holding a narrow lead over his Republican opponent, Mitt Romney. The president will use the campaign swing to portray himself as a champion of average, working-class Americans, and to portray Romney as a wealthy businessman before he entered politics.